Question

Your athlete is performing a dumbbell biceps curl. During the concentric phase of this exercise, at a constant speed, the athlete realizes that the exercise is easy at the beginning (elbow fully extended), more difficult in the middle (at 90 degrees of elbow flexion) and easy again at the end (at 135 degrees of elbow flexion). Explain why the athlete feels differences in external resistance during the concentric phase. If the client performed the same exercise with more speed, how would the ANGULAR MOMENTUM be affected? Explain by using concepts of biomechanics.

(This is biomechanics)

Answer 1

a) As we know that torque is equal to

  

value of is maximum at 90⁰ hence he will feel maximum torque at middle hence it is difficult for him to raise dumbbell at middle but initially angle is low so is low and at 135⁰ value of is again less hence torque is low in beginning and end therefore it is easier to do biceps curl  

If client is doing exercise at faster speed than angular momentum will increase because angular momentum is directly proportional to velocity